Research progress on yak grazing behavior and its influence on the soil properties of alpine grassland

doi:10.11686/cyxb2018372

Abstract

Abstract: Yak grazing is an important means of utilization of natural grassland in alpine ecosystems, and the herbage consumption, soil treading, and dung and urine excretion during grazing inevitably generate direct or indirect influences on grassland ecosystems. This paper reviews the basic characteristics of the 3 main impacts of grazing, foraging, trampling, and dung and urine deposition. Using this framework, research results relating to the behavioral ecology of grazing yaks are summarized and analyzed, and the influences and functional mechanisms of the animal behavioral processes on soil physicochemical and biological properties are explored. Through this approach, the impacts of grazing on soil carbon (C) and nitrogen (N) status, vegetation biomass and microbial communities in the alpine grassland were clarified. Results showed that foraging, trampling and excretion of dung and urine are important components of grassland C and N cycling and energy conversion. Forage nutrients not digested and utilized by grazing animals are returned to the soil as dung and urine, and this nutrient return is an important source of fertilization in the fragile natural grassland, and ensures the maintenance of soil nutrient balance and vegetation productivity. Compared to the influence of foraging behavior and excreta return, treading impacts emerge more slowly, but have a more permanent effect. Therefore, it is important to systematically elucidate the separate effects of herbage consumption, treading, and dung and urine deposition on the soil physical structure, nutrient dynamics, and herbage accumulation rate, in order to gain a comprehensive theoretical understanding the functional processes and mechanisms of yak grazing and how they influence the alpine grassland nutrient biogeochemical cycling in soil-vegetation systems. Such understanding could be helpful for providing scientific guidance for optimizing yak grazing patterns, maintaining the sustainable development of fragile ecosystems, and enhancing the construction of national ecological security safeguards on the Qinghai-Tibetan Plateau.

Key words: yak grazing, trampling, dung and urine deposition, soil structure, carbon and nitrogen dynamics, alpine ecosystem

DU Zi-yin, CAI Yan-jiang, WANG Xiao-dan, ZHANG Bin. Research progress on yak grazing behavior and its influence on the soil properties of alpine grassland[J]. Acta Prataculturae Sinica, 2019, 28(7): 186-197.

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